At PMH, 680 urine culture samples were evaluated for inclusion. Samples were not cultured if urinalysis was normal. Twenty-eight samples were excluded for the following reasons: a) duplicate samples with matching specimen and medical record numbers, but differing sensitivities (sample with most complete sensitivity data was included) (n=8)
; b) duplicate samples with matching medical record numbers and specimen numbers, but with multiple years listed (correct year was confirmed via electronic medical records and duplicate was excluded) (n=9)
; c) samples that grew multiple pathogens (n=52)
. A total of 652 samples were included from PMH, which included all samples that met our inclusion criteria. Of the samples from PMH, 58% were from outpatient clinics.
At BPH, 760 samples were evaluated for inclusion from BPH. We included a total of 92 samples, with the remainder excluded for either no growth of a single organism, or growth of multiple organisms. The low culture positivity rate at BPH vs PMH may be explained by the fact that specimens were often cultured at BPH without a prior microscopy or dip or despite a negative microscopy or dip. Seventy-three percent of eligible samples from BPH were from outpatient clinics.
Urine dipsticks, as well as urine microscopy, culture, and sensitivities, were carried out inconsistently at both institutions. Cultures at PMH were generally performed on samples with >10 white blood cells (WBC) per high power field (hpf) on microscopy; however, some had cultures performed if they were only positive on dipstick testing for blood, leukocyte esterase, or nitrites. Sometimes cultures were performed without prior microscopy or with normal microscopy.
Information on patient demographics is listed in . There were no significant differences in the age distribution or gender of patients when comparing the private and public sectors. Inpatients were more likely to be male (P
0.002) and to be less than 18 years old or 65 years and older (P<0.001). There were broadly equivalent percentages of HIV-positive patients in the public and private settings, although patients were more likely to have an unknown or undocumented HIV status at PMH (P<0.001). However, at PMH, almost half (49%) of the patients with known HIV status were HIV-positive compared to just over a quarter (26%) at BPH (P
Uropathogens from PMH and BPH are listed in . There were significant differences in the pathogens isolated when comparing private to public settings (P
0.001) and inpatient to outpatient settings (P
0.007). E. coli
was the most common pathogen in all settings and accounted for 63% of isolates at both PMH and BPH. Sixty-six percent of outpatient isolates were E. coli
, compared to 58% in inpatient settings. At PMH, Klebsiella
species were responsible for 14% of UTIs followed by Proteus
species that were responsible for another 5%. Klebsiella
species each accounted for 7% of isolates at Bokamoso.
At BPH, 10 isolates (11%) were found to produce ESBL. Six were E. coli isolates, three were Proteus isolates, and one was a Klebsiella isolate.
illustrates overall resistance patterns for all uropathogens stratified by study site. Given that it was the predominant organism, analysis focused on resistance patterns of E. coli
isolates (). Among E. coli
isolates, there was no significant difference in resistance to ampicillin when comparing samples from in- and outpatient settings. However, resistance was significantly higher among samples from patients at PMH compared to those from BPH (86% vs. 76%; P
0.034). Resistance to gentamicin was higher among samples from inpatients compared to outpatients (P
0.015) and the public sector compared to the private sector (P
0.018). Resistance to co-trimoxazole was also higher among samples from inpatients (P
0.017) and the public sector (P
0.034). Nearly 30% of E. coli
isolates at PMH were resistant to amoxicillin/clavulanate compared with 11% from BPH (P
0.016). However, another 13% of samples from BPH demonstrated intermediate resistance.
Antimicrobial resistance patterns of all UTI pathogens.
Antimicrobial resistance patterns of E. coli isolates.
Resistance patterns to nitrofurantoin, ceftazidime, and ciprofloxacin did not differ significantly based on setting (P>0.05). Overall resistance to nitrofurantoin was ten percent or lower in all settings. Twenty-five percent of E. coli isolates were resistant to ciprofloxacin in the inpatient settings in both the public and private sectors with somewhat lower resistance in outpatient settings.
Data were not available for resistance patterns of first- or second-generation cephalosporins at PMH. There was no significant difference in resistance patterns for cefazolin or cefuroxime at BPH when comparing inpatient and outpatient settings (P>0.05). There was 18 percent resistance to both cefazolin and cefuroxime among E. coli isolates at BPH, with an additional 10 percent and three percent showing intermediate resistance respectively.
Sub-analyses also compared the differences in microbiology and antimicrobial susceptibilities between samples from pediatric (<18 years old) and adult populations. There were no significant differences in the pathogens causing UTI when comparing these populations. However, compared to those from adult patients, E. coli
isolates from pediatric patients did have higher levels of resistance to gentamicin (23% vs 11%) (P
0.045) and co-trimoxazole (88% vs 74%) (P
We further explored the association between known HIV status, uropathogens, and antimicrobial resistance of E. coli isolates. HIV status had no significant impact on the uropathogens that caused UTI in any setting. However, HIV status was associated with a difference in the resistance of E. coli isolates to co-trimoxazole. E. coli isolates from known HIV-positive patients demonstrated significantly higher resistance to co-trimoxazole compared to isolates from known HIV-negative patients (95% vs. 72%) (P<0.001). HIV status did not affect resistance patterns to the other antimicrobials that we examined.